Stethomostus

Taxonomy

Family: Tenthredinidae
Family common name: common sawflies
Subfamily: Blennocampinae
Tribe: Phymatocerini
Genus: Stethomostus Benson, 1939
Subgenera: none

Background

The Tenthredinidae are the most species-rich family and are found throughout the world, in all continents but Antarctica. They are known as the “common sawflies.” They can generally be recognized by a cylindrical body and long, segmented antennae. Otherwise, they come in a variety of colors, sizes, and forms (Goulet 1992).

Sawflies in the subfamily Blennocampinae have a diverse set of life histories and habits. Many species are restricted to subtropical and tropical regions, but the genus is still fairly species-rich in North America. Blennocampinae includes many sawflies that feed on ornamental and forestry crops. This subfamily can be recognized by wing venation and bidentate mandibles (Smith 1969d).

Stethomostus is monotypic in North America. Stethomostus fuliginosus is about 6–6.5 mm in length and entirely black with white markings on fore tibia and partially darkened wings (Smith 1969d).

Diversity

There are seven described extant species worldwide. One species occurs in North America (Taeger et al. 2018).

Diagnostic characteristics

Subfamily characters

Genus characters

May be confused with

Stethomostus can be confused with similar species in the subfamily Blennocampinae. It can be distinguished from most other genera by the length of the third antennal segment, and from similar species in Eutomostethus by the furcate foretibial spur and the straight apex to veins 2A and 3A of fore wing (Smith 1969d, Goulet 1992).

Exotic pest species of concern

none

Host associations

Stethomostus fuliginosus feeds on species of Ranunculus (buttercup) (Goulet 1992).

Life history

unknown

Distribution

World: This genus is known from North America, throughout Europe and Russia, and in China, Japan, and Vietnam (Taeger et al. 2018).

North America: Stethomostus fuliginosus was introduced to North America and now occurs in northeastern United States, in New England west to the Great Lakes region, and into New Brunswick in Canada (Smith 1969d).

Map data from: GBIF.org (29 October 2019) GBIF Occurrence Download Stethomostus

Details about data used for maps can be found here.

Stethomostus fuliginosus female dorsal habitus; photo by J. Orr, WSDA

Stethomostus fuliginosus female dorsal habitus; photo by J. Orr, WSDA

Stethomostus fuliginosus female face; photo by Q. Baine, WSDA

Stethomostus fuliginosus female face; photo by Q. Baine, WSDA

Stethomostus fuliginosus male lateral habitus; photo by J. Orr, WSDA

Stethomostus fuliginosus male lateral habitus; photo by J. Orr, WSDA

Stethomostus fuliginosus male dorsal habitus; photo by J. Orr, WSDA

Stethomostus fuliginosus male dorsal habitus; photo by J. Orr, WSDA

Stethomostus fuliginosus male face; photo by Q. Baine, WSDA

Stethomostus fuliginosus male face; photo by Q. Baine, WSDA

Stethomostus fuliginosus wings; photo by J. Orr, WSDA

Stethomostus fuliginosus wings; photo by J. Orr, WSDA